20-somethings have health, time, and lack the finances to take other kinds of vacations. Many "working-age" people have limited vacation and there are kids, work, and school schedules to juggle. And they have more money to do non-BPing trips.
A lot of Americans, by their 60s and 70s, aren't in shape to do a BPing trip. Although I've had my butt kicked on snow slopes and the Whitney Trail by 80-year-olds.
>"some young whippersnapper even congratulated us on getting there"
The last time I hiked up Half Dome, on a lark, I decided to count how many people half my age I hiked past before any hiked past me. The answer was "all of them", I lost count at 150. Age & treachery beat youth & beauty every time. I'm assuming you uttered the words "whippersnapper" to him.
Colin Fletcher ("The Man Who Walked Through Time", "The Complete Walker", etc) was a high mileage hiker his entire 85 years. Mowed down by an SUV at age 80, his remarkable recovery was attributed to a lifetime of exercise.
I do notice a trend, though, among many 20-somethings to do a vigorous day (hiking, mountain biking, skiing, etc) and the some other activit(ies) the rest of the week/weekend more now than 30-40 years ago.